Fix various issues with Seq.(method)

Spotted by lucasb++

src/core/Any.pm

@@ -65,6 +65,8 @@ my class Any { # declared in BOOTSTRAP
     multi method Slip() { self.list.Slip }
     proto method Array(|) is nodal { * }
     multi method Array() { self.list.Array }
+    proto method Seq(|) is nodal { * }
+    multi method Seq() { self.list.Seq }
 
     proto method hash(|) is nodal { * }
     multi method hash(Any:U:) { my % = () }

src/core/List.pm

@@ -691,7 +691,6 @@ my class List does Iterable does Positional { # declared in BOOTSTRAP
 
     multi method list(List:D:) { self }
 
-    proto method Seq(|) is nodal { * }
     multi method Seq(List:D:) { Seq.new(self.iterator) }
 
     method sink(--> Nil) { }

src/core/Seq.pm

@@ -24,8 +24,8 @@ my role PositionalBindFailover {
             ?? $!list
             !! ($!list := List.from-iterator(self.iterator))
     }
-    method list() {
-            List.from-iterator(self.iterator)
+    multi method list(::?CLASS:D:) {
+        List.from-iterator(self.iterator)
     }
 
     method iterator() { ... }
@@ -74,26 +74,16 @@ my class Seq is Cool does Iterable does PositionalBindFailover {
         )
     }
 
-    method eager {
-        List.from-iterator(self.iterator).eager;
-    }
+    multi method eager(Seq:D:) { List.from-iterator(self.iterator).eager }
+    multi method List(Seq:D:)  { List.from-iterator(self.iterator) }
+    multi method Slip(Seq:D:)  { Slip.from-iterator(self.iterator) }
+    multi method Array(Seq:D:) { Array.from-iterator(self.iterator) }
+    multi method Seq(Seq:D:)   { self }
 
     method Capture() {
         self.List.Capture
     }
 
-    method List() {
-        List.from-iterator(self.iterator)
-    }
-
-    method Slip() {
-        Slip.from-iterator(self.iterator)
-    }
-
-    method Array() {
-        Array.from-iterator(self.iterator)
-    }
-
     method elems() {
         nqp::if(
           self.is-lazy,